In an environment of volcanic and plutonic rocks such as the Central Hoggar, the knowledge of groundwater flows and their residence time is of prime importance. This is especially the case in the arid zone of Central Sahara where the main town of southernmost Algeria, Tamanrasset, with its rapidly growing population (>200,000 inhabitants extreme South of Algeria), put an important pressure on the local aquifers. Central Hoggar belongs to the LATEA metacraton, which is a Precambrian basement largely fractured and invaded by Cenozoic mostly basaltic volcanic rocks. In addition to superficial alluvial reservoirs, these two contrasted lithologies and large and deep faults determine the geometry of the aquifers and the nature and composition of water. We show here that distinct aquifers exist along faults oriented from NW-SE to NE-SW with no lateral communications. Some waters are in equilibrium with the Cenozoic volcanic system and others with the Precambrian basement although the latter bear often a Cenozoic volcanic signature attributed to volcanic coating along faults at depth. Alluvial, volcanic and Precambrian aquifers display contrasted measured pCO2 and specific conductivity (SC) values, stable (δ18O, δ2H), 87Sr/86Sr, 3H, δ13C and 14C isotopes. A major role is given to the Pan-African Adriane shear zone (ASZ), running just east of Tamanrasset, along which waters with high residence time (0.2